/**************
 * readtest.c *
 **************/
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
main()
{
	int pipe_fd[2];
	pid_t pid;
	char r_buf[100];
	char w_buf[4];
	char* p_wbuf;
	int r_num;
	int cmd;
	
	memset(r_buf,0,sizeof(r_buf));
	memset(w_buf,0,sizeof(r_buf));
	p_wbuf=w_buf;
	if(pipe(pipe_fd)<0)
	{
		printf("pipe create error\n");
		return -1;
	}
	
	if((pid=fork())==0)
	{
		printf("\n");
		close(pipe_fd[1]);
		sleep(3);//确保父进程关闭写端
	    r_num=read(pipe_fd[0],r_buf,100);
printf(	"read num is %d   the data read from the pipe is %d\n",r_num,atoi(r_buf));
		
		close(pipe_fd[0]);
		exit(1);
	}
	else if(pid>0)
	{
	close(pipe_fd[0]);//read
	strcpy(w_buf,"111");
	if(write(pipe_fd[1],w_buf,4)!=-1)
		printf("parent write over\n");
	close(pipe_fd[1]);//write
		printf("parent close fd[1] over\n");
	sleep(10);
	}	
}
